How to bend/create nice angle without warping model
As you have V angles, you should not have modeled rectangular angles in the first place, it's better to first follow the whole shape:

Extrude:

Give it a Solidify modifier (Complex mode to give it even thickness):

Apply the modifier, round the angles with bevel operations:

Correct the topology with the knife (K to activate, Z to cut through), dissolve unwanted edge loops with CtrlX:

Give your object some Boolean modifiers in order to cut of the holes, etc: